1. Field of the Invention
The present invention relates to an image processing apparatus and method capable of using a removable medium for storage of image data, and a storage medium storing a computer program for execution of the image processing method.
2. Description of the Related Art
In a conventional image processing apparatus such as a multi-function peripheral, image data read by a scanner or received by a FAX machine or the like is stored into a memory such as a RAM and a hard disk of the image processing apparatus. To increase the image data storage capacity, an additional RAM or hard disk must be added to the apparatus, which requires technical knowledge.
To obviate this, an image forming apparatus capable of using a removable medium for storage of image data has been proposed (Japanese Laid-open Patent Publication No. 2007-67476). Removable media have recently been gained widespread use, and special technical knowledge to utilize them has become less needed.
Japanese Laid-open Patent Publication No. 8-265527 proposes a technique for saving image data into an external storage unit, if there is no sufficient free space in the RAM or hard disk for storage of image data as a result of image being unable to be output due to a printer abnormality or the like. When the printer is restored to its normal state, the saved image data is retrieved from the external storage unit and image output is continued.
However, the removable medium has a nature that it is lower in access speed and much restricted in the number of writable (erasable) times as compared to the RAM and hard disk.
When the removable medium is used for storage of image data, therefore, image data saving and retrieval must be made efficiently, and image data to be saved and retrieved must be selected in consideration of the nature of removable medium to maintain the performance of image processing apparatus.